Dealing with extreme heat

Source– The post is based on the article “Dealing with extreme heat” published in “The Hindu” on 17th April 2023.

Syllabus: GS3- Disaster and disaster management

Relevance– Heat waves and stress

News– The article explains the increasing heat distress in India.

What are some data and facts associated with heat stress in India?

Around 350 million Indians were exposed to strong heat stress between April and May 2022. Between 1990 and 2019, summer temperatures on average rose by 0.5-0.9°C across districts in Punjab, Haryana, Uttar Pradesh, Bihar and Rajasthan. Around 54% of India’s districts have also seen a similar rise in winter temperatures.

Between 2021 and 2050, it is expected that the maximum temperature will rise by 2-3.5°C in 100 districts and by 1.5– 2°C in around 455 districts. Similarly, winter temperatures will rise between 1°C and 1.5°C in around 485 districts.

Indian cities are impacted by urban heat island effect. Temperatures are 4-12°C higher than rural outlying areas. Humidity has exacerbated the felt temperature.

More recently, Northern India has seen significant variability in the weather. Cold weather in January was followed by a heat wave in February and early March, and hailstorm and heavy rain in the past few weeks.

What are the impacts of heat stress?

Weather variability has consequences for agriculture. For example, 90% of India’s cumin production is from Gujarat and Rajasthan. The recent weather variability has destroyed the majority of the cumin crop in Rajasthan.

Rising temperatures have also led to unliveable cities. For labourers, heat exposure leads to a loss of 162 hours per year, as per one study.

A rise in temperatures directly impacts labour productivity. About 50% of India’s workforce is estimated to be exposed to heat during their working hours. This includes marginal farmers, labourers at construction sites and street vendors and gig economy workers.

What is the way forward to mitigate the challenges related to heat waves distress?

Greening could help mitigate part of the problem. Ideally, for every urban citizen in India, there should be at least seven trees in the urban landscape.

Development plans for Tier 2 and Tier 3 cities should increase urban surface area that is permeable. The push should be on increasing the density and area of urban forests.

Expanding wetlands and restoring dead and decaying lakes may also help ensure ecological functioning along with reducing urban heat.

There is a need to reduce the urban heat island effect. This will require a push for greater usage of permeable materials in civic infrastructure and residential construction.

Urban layouts such as brick jalis for ventilation and terracotta tiles to allow hot air to escape may be considered. Curbing anthropogenic heat emissions from vehicles and factories will be helpful.

Urban building standards should be upgraded to avoid usage of heat-absorbent galvanised iron and metal roof sheets. Using cleaner cooking fuels will reduce indoor air pollution. It may also help reduce urban heat. Streets with low ventilation may need further expansion.

Other measures can also be considered. These are embracing public transportation, reducing personal vehicle usage and reducing the size of landfills.

Methane production from mountainous landfills may lead to fires. It increases the urban heat and weather variability in our cities. Waste segregation, along with solid waste management at source, can be helpful.

There is a need to improve forecasting ability. It includes the potential impact of heat on food production.

Current econometric models associated with food inflation primarily look at the variability in the monsoon, minimum support prices and vegetable prices. Local heat trends need to be added, given their impact of heat on food production, storage and sale.

There is a need for detailed policies and guidelines on weather variability and urban heat management at the State, district, city and municipality ward levels.

The urban design of Chandigarh is an example. It considers climate responsiveness as a key factor. A large green belt of mango trees was also planted around the city to reduce urban sprawl and to serve as a buffer between the residential city and the industrial suburbs.

Sukhna lake was constructed to help in cooling the city, while small water bodies were developed near large buildings. Parks were planned out in every sector, along with tree plantations alongside all the major roads. Large forest areas were also reserved.